1. Field of the Invention
The bushwood chopper and spreader attachment according to the invention is adapted to be carried by a crane-type vehicle having an articulated boom adapted to transmit a rotational movement to a vertical driving shaft of the attachment. The shaft is centrally secured in horizontally superposed metallic discs provided with freely rotating cutters extending at the periphery of the discs. The centrifugal force projects the cutters radially outside the perimeter of the discs but are pivotally pushed inside the periphery upon a sudden encounter of a resisting or unyielding body.
The cutters have a linear speed adapted to spread the chopped residue of trees over a large surface of the surrounding ground in order to regenerate and increase the quality of the earth.
2. Prior Art
U.S. Pat. No. 3,574,989, is directed to a grinder attachable to a tractor. The grinder is designed to rotate about a horizontal axis with cutting knives also provided about horizontal axes. The knives move in a plane perpendicular to their cutting edge and upon obstruction will flip 360.degree. backwards without any stopping means. After this flipping action, the knives return to their operating position with the heel first. This is a waste of cutting time inasmuch as the heel may hit another obstacle before returning to a truly cutting position.
In U.S. Pat. No. 4,509,315, the patentee makes use of pivoting blades makes a full rotation about their axis and have an offset portion to shield the pivotal member.
Boehm discloses, in U.S. Pat. No. 4,218,022, frail knives for combining harvester wherein the cutter edges are pivotally secured to a drum. These knives operate in cooperation with stationary leg portions in order to chop straw.
The demolition mill disclosed in U.S. Pat. No. 3,826,437, makes use of a plurality of free swinging hammers 52 for demolishing material fed into an inlet throat. The hammers are mounted on a plurality of shafts 39 extending between large parallel wheels.